Abstract

Among many types of frequency changers, the Unrestricted Frequency Changer (UFC) has unique characteristics of unlimited output frequency and the ability to supply reactive power to the input supply system. Thus, its employment can be superior in many applications, such as speed control of a.c. motors and reactive power compensation. However, its practical realization is cumbersome and hence has limited its employment in real systems. This paper summarizes the design, implementation, and the experimental results of a laboratory model UFC system employing GTO thyristors.